The present invention relates to component mounters and mounting methods such as for mounting electronic components on substrates.
Component mounters, typically for mounting electronic components, pick up components stored in a feeder carriage using a mounting head with a suction nozzle, and transfer them to a target substrate to mount on predetermined mounting points. Before mounting components on the substrate, each component is visually recognized to identify its type and to detect any positional deviation.
This recognizing operation takes place before mounting, typically in the following way. A camera captures an image of a component held by the mounting head from underneath. A line camera is often used as means of capturing component images. The line camera is equipped with a line sensor comprising numerous CCD elements aligned in one dimension. The target object whose image is to be captured is passed over the line sensor and scanned, generating two-dimensional image data.
This type of conventional component mounter and mounting method often employs two or more suction nozzles on the mounting head to improve the mounting efficiency. These multiple nozzles on the head pick up required components from each parts feeder in the feeder carriage according to the mounting sequence, and pass the component over the camera for image capture and recognition of each component.
The above line camera has the following disadvantage of recognizing multiple components held by multiple suction nozzles.
The line camera recognizes components by scanning a target component to obtain a two-dimensional image from a set of one-dimensional images. An appropriate scanning speed for each target component exists for capturing an image at satisfactory resolution. Accordingly, when the camera continuously scans multiple components held by multiple suction nozzles, the scanning speed needs to be changed for each component.
The scanning speed of the line camera for each component in the conventional electronic component mounting method is described next with reference to FIG. 4.
FIG. 4 is a graph illustrating changes in the scanning speed when capturing an image, i.e., the horizontal movement speed of the mounting head during capture of the image in the conventional electronic component mounting method. In FIG. 4, V1, V2, and V3 are appropriate scanning speeds for respective electronic components (110, 120, and 130 in FIG. 3). Here, their relations are V3 greater than V1 greater than V2.
It is apparent from the graph that the horizontal movement speed of the mounting head is switched to achieve the scanning speeds V1, V2, and V3 suitable for each component when capturing images of the components 110, 120, and 130. In addition, a predetermined approaching time is required when switching the speed to obtain a stable scanning speed. In order to capture images at stable scanning speed for all three components, three steps of approaching times T1, T2, and T3 are required to be set.
Consequently, the total scanning time T is greatly prolonged because these approaching times are added to the net image capturing time resulting in much reduced recognition efficiency. The conventional component mounting method requires a different scanning speed to be set for each electronic component in order to recognize each component while continuously moving multiple components. Accordingly, the total scanning time T becomes longer, reducing recognition efficiency.
The present invention aims to offer a component mounter and mounting method which reduces recognition time and improves mounting efficiency for recognizing images of each component while moving multiple components continuously.
The component mounter of the present invention comprises the following:
(a) a component feeder carriage;
(b) a mounting head with several suction nozzles for picking up components from the feeder carriage; and
(c) a recognizer disposed on a movement route of the mounting head for recognizing components.
Components picked up are scanned at the slowest speed required for recognizing each component while relatively moving these components integrally against the recognizer. After recognizing each of these components, these are mounted on a mounting target (such as a substrate).
The above configuration eliminates the need of approaching time after switching the speed for scanning each component, reducing the total recognition time to realize highly efficient component mounter.
The component mounting method of the present invention comprises the following steps:
(a) picking up components from the component feeder carriage by several suction nozzles provided on the mounting head;
(b) recognizing each component with the recognizer by relatively moving each component picked up integrally at a predetermined speed against the recognizer disposed on the movement route of the mounting head; and
(c) mounting each component on a mounting target.
The above predetermined speed is the slowest speed in scanning speeds required for recognizing each component picked up.
Another mounting method of the present invention comprises the next steps:
(a) picking up components from the feeder carriage by several suction nozzles provided on the mounting head;
(b) calculating scanning speed for recognizing each component picked up;
(c) identifying the slowest speed in these calculated scanning speeds;
(d) scanning these components integrally against the recognizer disposed on the movement route of the mounting head at the above slowest speed by moving the mounting head;
(e) recognizing each component during scanning; and
(f) mounting each component on a mounting target.
This method integrally moves multiple components relative to the recognizer for scanning at the slowest scanning speed in scanning speeds set for each component by relatively moving these components against the recognizer. This eliminates the approaching time required for switching the scanning speed for each component, reducing the total recognition time and achieving efficient component mounting.